Centrifugal pump

ABSTRACT

A centrifugal pump comprising a housing with a discharge opening and an impeller in the housing, the impeller being of tubular form and having peripheral outlet openings arranged to discharge into the interior of the housing and an axial inlet opening isolated from the interior of the housing. The pump further has means for guiding fluid in the interior of the housing to the discharge opening, the guiding means comprising a tubular member having an axial outlet opening and peripheral inlet openings, the inlet openings being provided with vanes for guiding fluid inwardly through the inlet openings into the interior of the tubular member.

United States Patent Theron [451 Feb. 4, 1975 CENTRIFUGAL PUMP 2,775,945 1/1957 Arutunoff 415/501 [761 Invent a" 9 1 Theron, 33831851 51132? 23532511531111: 3131135313133 Roolwal, Dlsmct Righmond, p 3,154,019 10/1964 Hoyt 415/187 Province, South Afrlca 3,438,329 4/1969 Fuller 415/199 [22] Filed: Aug. 6, 1973 E w n L F h Primary xamineri iam ree [211 App! Assistant Examiner L. J. Casaregola [30] Foreign Application Priority Data [57] ABSTRACT Sept. 13, 1972 South Africa 72/726250 A centnfugal pump comprising a housmg with a dis- Oct. 13, 1972 South Africa 72/727314 charge p g and an impeller in the g g, the 52] us. c1 415/199, 415/213, 415/501 ig g fgs g gf [51] Int. Cl. F04d 13/14, F04d 29/28, F04d 29/44 of the housing and an axial inlet opening 1solated from [58] Field of Search ..415/77,187,l88,199 A,

415/213 R 501 209 182 185 416/178 the interior of the housmg. The pump further has 179 means for guiding fluid in the interior of the housing t0 the discharge opening, the guiding means comprising a tubular member having an axial outlet opening [56] References Clted and peripheral inlet openings, the inlet openings being UNITED STATES PATENTS provided with vanes for guiding fluid inwardly through 1,149,638 8/1915 Davidson 415/188 the inlet openings into the interior of, the tubular 1,231,331 6/1917 Kite et al. 415/213 man/EL 1,433,995 10/1922 Fowle 415/213 1,909,052 5/1933 Froisland 415/213 8 Claims, 6 Drawing Figures CENTRIFUGAL PUMP BACKGROUND TO THE INVENTION This invention relates to a pump. In particular the invention relates to a centrifugal pump.

According to the invention there is provided a centrifugal pump comprising a housing having a discharge opening, an impeller in the housing, the impeller being of a tubular form and having a peripheral outlet opening arranged to discharge into the interior of the housing, and an axial inlet opening isolated from the interior of the housing, and means for guiding fluid in the interior of the housing to the discharge opening.

The fluid guiding means may comprise a tubular member having an axial outlet opening and a peripheral inlet opening, the inlet opening being provided with a vane for guiding fluid inwardly through the inlet opening into the interior of the tubular member. Preferably, the tubular member has a plurality of peripheral inlet openings. Along the margin of each peripheral inlet opening may be provided a pair of vanes.

The impeller may have a plurality of peripherally spaced outlet openings. Each outlet opening of the impeller may be provided with a vane for imparting a rotary motion to fluid in the interior of the impeller and for guiding the fluid through the outlet opening of the impeller. Each outlet opening of the impeller may further be provided with means for deflecting the fluid axially relative to the impeller as it passes through the outlet opening of the impeller. The impeller may be fabricated from a metal tube. Alternatively, if desired, it may be in the form of a moulding of a synthetic plastics material.

The housing may be cylindrical, and the fluid guiding means may be spaced axially from the impeller in the housing.

The pump may include drive means for the impeller in the form of a shaft connected to the impeller.

Preferably, the fluid guiding means is located downstream of the impeller.

The pump may be a multi-stage pump, the pump comprising a plurality of impellers and fluid guiding means, as described, operatively interconnected to one another. The impellers and the fluid guiding means may be mounted in a common housing and the impellers may have a common drive.

Also according to the invention, there is provided an impeller, suitable for use in a centrifugal pump, the impeller being in the form of a tubular member having an axial inlet opening and a peripheral outlet opening.

Further according to the invention, there is provided means suitable for guiding fluid in the interior of a housing of a centrifugal pump to a discharge opening of the pump, the means comprising a tubular member having an axial outlet opening and a peripheral inlet opening, the inlet opening being provided with a vane for guiding fluid inwardly through the inlet opening into the interior of the tubular member. Preferably, the fluid guiding means has a plurality of peripheral inlet openings, each opening being provided with a pair of vanes.

The invention will now be described, by way of examples, with reference to the accompanying drawings, in which:

FIG. 1 shows an axially exploded three-dimensional view of an impeller in accordance with the invention;

FIG. 2 shows a sectional plan view of the impeller of FIG. 1, along line IIII in FIG. 1;

FIG. 3 shows an axially exploded three-dimensional view of fluid guiding means in accordance with the invention;

FIG. 4 shows a plan view of the fluid guiding means of FIG. 3;

FIG. 5 shows a sectional side elevation of a pump in accordance with the invention; and

FIG. 6 shows an exploded three-dimensional view of the pump of FIG. 5.

In FIGS. 1 and 2 of the drawings. reference numeral 10 generally designates an impeller fabricated from a steel tube in accordance with the invention. The impeller comprises a tubular member 12 provided with an end cover in the form of a disc 14 at one end thereof. The other end of the tubular member 12 is provided with a stepped flange 16. The end cover 14 and stepped flange 16 are coaxially welded to the opposite ends of the tubular member 12. The welds extend peripherally as at 18 and 20, and the tubular member 12 is welded to the flange portion 16.1 of the stepped flange 16. The end cover 14 is provided with an axially positioned outwardly facing threaded socket 14.1 for connection to a drive shaft (not shown in FIG. 1).

The stepped flange 16 defines an axial inlet opening into the impeller 10, and the tubular member 12 has a pair of diametrically opposed outlet openings 22. The outlet openings 22 are each provided with a pair of rectangular vanes 22.1 and 22.2. The tubular member 12 is a metal and the outlet openings 22 are provided by forming a pair of diametrically opposed I-shaped slits in the wall of the tubular member, the upright of each I extending axially and the cross members of each I extending circumferentially. Each slit thus defines a pair of opposed rectangular flanges, one of which is bent radially inwardly to form the vane 22.1 and the other being bent radially outwardly to form the vane 22.2. The vanes 22.1 all extend in the same circumferential direction at an angle to the curved wall of the tubular member 12; and the vanes 22.2 all extend in the opposite circumferential direction at an angle to said tubular member.

Each outlet opening 22 is provided with deflectors in the form of a plurality of metal platelets 24. The platelets 24 are welded to the outer surface of the vane 22.1 in axially spaced relationship. Each platelet 24 is welded edge-on on the vane 22.1, and extends substantially circumferentially away from the longitudinal edge of the vane. The platelets 24 are curved, and curve towards the disc 14 in a direction away from said longitudinal edge. The curves of the platelets 24 and the positions where they are welded to the vane 22.1 are illustrated by broken lines 26 in FIG. 1.

Referring now to FIGS. 3 and 4, reference numeral 28 generally designates fluid guiding means or a collector in accordance with the invention. The collector comprises a tubular member 30 provided with an end cover 32 at its one end, the other end being externally screw-threaded, as at 34. The collector 28 has an axial outlet 36 and a plurality of circumferentially spaced peripheral inlets 38 adjacent the end cover 32. Each inlet 38 is substantially rectangular and has a pair of vanes 38.1 and 38.2. The vane 38.1 is welded along one side of the inlet to extend inwardly at an angle to the curved wall of the tubular member 30, or may be formed by bending a portion of said curved wall inwardly, as at 38.11; and the vane 38.2 is welded along the other side of the inlet to extend outwardly at an angle to the said curved wall. The vanes 38.1 all extend in the same circumferential direction; and the vanes 38.2 all extend in the same circumferential direction, which is opposite to thedirection in which the vanes 38.1 extend. The end cover 32 has a central opening 32.1 therethrough, and an annular seal 32.2 is provided for said opening, fast with the inner surface 32.3 thereof.

Reference will now be made to FIGS. 5 and 60f the drawings, which show a two-stage pump in accordance with the invention. In FIG. 5, reference numeral 40 generally designates the pump; and in FIG. 6 each part is designated by a specific reference numeral. Unless otherwise specified, like reference numerals refer to like parts. i

The pump 40 comprises a housing, generally designated 42, and made up of a pair of steel cylinders 44.1 and 44.2 joined to each other by a threaded connecting socket 46. The free or outer end of the cylinder 44.1 is connected to a threaded socket 48 having a passage 48.1 therethrough. The wall of the passage 48.1 is provided with an axially inwardly facing circumferential shoulder 48.2.

A first stage impeller 10.1 is coaxially mounted in the housing 42 adjacent the socket 48 on the end of an axial drive shaft 50. The end of the drive shaft 50 is threaded and engages with the socket 14.1 of the end cover 14 of the impeller 10.1. The body 16.2 of the stepped flange 16 of the impeller 10.1 nests in the socket 48 adjacent the shoulder 48.2, the stepped flange 16 and socket 48 having sliding clearance therebetween. This clearance is such that a substantially liquid tight seal is provided between theflange 16 and socket 48.

The first stage collector 28.1 is mounted, concentrically in the housing 42, downstream of and axially spaced from the impeller 10.1. The screw-threaded end 34 of the collector (FIG. 3) is screwed into the socket 46, one end of which is internally screw threaded. The drive shaft 50 extends axially through the collector 28.1 and passes rotatably through the opening 32.1 of its end cover 32, the seal 32.2 seating sealingly against the shaft 50. v

The socket 46 has a circumferential shoulder 46.1 at its other end and directed axially away from the collector means 28.1. A second stage impeller 10.2 is mounted on the drive shaft 50, axially downstream of the socket 46. The flange 16 of the impeller 10.2 nests sealingly in the socket 46 adjacent the shoulder 46.2, in the manner described for the impeller 10.1 and socket 48. In FIG. 5 the flange 16 is however shown clear of the socket 46, for ease of illustration. The end cover 14 of the impeller 10.2 has a central passage 14.2 therethrough instead of the socket 14.1 shown in FIG. 1. The shaft 50 extends through the passage 14.2 and is connected to the impeller 10.2 by a threaded longitudinally split clamping socket 52 engaging with a nut 52.1.

A second stage collector 28.2 is mounted downstream of and axially spaced from the impeller 10.2. The screw threaded end 34 of the collector 28.2 is screwed into the upstream end of an internally screw threaded reducing socket 54, at the downstream end of the housing 42. The shaft 50 passes through the collector 28.2, as described for the collector 28.1.

The socket 54 serves to connect the cylinder 44.2 to a pipe length 56, the passage 54.1 through the socket 54 forming the discharge of the housing 42. At the end of the pipe length 56 remote from the socket 54 a connecting socket 58 is provided.v The connecting socket 58 is suitable for connection to the rising main of a borehole or the like (not shown). A spider bearing 60, located in the socket 58, engages the shaft 50 to locate it radially.

Each impeller 10, and its downstream collector 28. must be arranged so that the vanes thereof. respectively 22.2 and 38.2, extend circumferentially in the same direction. This is as shown by arrow 62 in FIGS. 2 and 4. Preferably the two impellers and the two collectors all have their respective vanes 22.2, 38.2 extending circumferentially in the direction of arrow 62.

The pump 40 is suitable for use as a borehole pump. When it is used as a borehole pump, the socket 58 will be connected to the rising main of the borehole; the

drive shaft 50 will be connected to a drive shaft extending down the borehole (not shown); and the socket 48 will be below water level or will be connected to a conduit which extends below water level in the borehole. The conduit, rising main and borehole drive shaft are not shown in the drawings. For operation, the pump 40 must be filled with water by locating it below water level, or by priming it by another suitable method.

Rotation of the shaft 50 in the direction opposite to arrow 62 (FIGS. 2 and 4) will cause water to be drawn upwardly through the socket 48 into the impeller 10.1. Centrifugal force will then cause water in the impeller 10.1 to be thrown outwardly through the outlet openings 22, the vanes 22.1, 22.2 serving to guide the water through said outlet openings and aiding in rotation of water in the impeller. The water expelled from said openings will circulate through the cylinder 44.1 circumferentially in the direction opposite to arrow 62 and axially in the direction of arrow 64 (FIG. 5). The platelets 24'serve to deflect the water in the axial direction of arrow 64, as it passes through the outlet openings 22.

' The water will then pass inwardly into the collector 28.1 through the inlets 38. The vanes 38.1, 38.2 serve to guide the water into the collector 28.1 and towards its outlet 36. From the outlet 36 the water passes into the impeller 10.2. The impeller 10.1 and collector 28.1 form the first stage of the pump, and the impeller 10.2 and collector 28.2 form the second stage of the pump. The operation of the second stage of the pump is the same as the operation of the first stage of the pump, and the two stages together serve to reinforce one another.

From the second stage the water passes outwardly via the socket 54 which forms the discharge for the housing 42, and upwardly through the pipe length 56 and into the rising main of the borehole pump.

If desired, a rotor or propeller (not shown) may be provided upstream of the first stage impeller 10.1 for aiding in drawing the water into the pump 40.

I claim:

1. A centrifugal pump comprising 'a housing having a discharge opening, an impeller in the housing, the impeller being of a tubular form having an axial inlet opening isolated from the interior of the housing and adapted to discharge into the interior of the housing, and a guide means for guiding fluid in the interior of the housing to the discharge opening, the guide means being arranged axially with respect to the impeller and comprising a tubular member having substantially the same diameter as the impeller with an axial outlet opening and being adapted to guide fluid inwardly into the interior of the guide means, the impeller and guide means, each further comprising a hollow cylindrical member having at least one elongated opening in its peripheral surface, each said opening having two of its defining edges substantially, axially aligned, and each said opening having a vane attached to at least one of said defining edges, each said vane being jointed to a corresponding defining edge in such a manner that each said vane and said peripheral surface cooperate to form an angle therebetween.

2. A pump according to claim 1, wherein the fluid guide means has a plurality of peripheral inlet openings, and wherein a pair of vanes is provided along the margin of each opening.

3. A pump according to claim 1, wherein the impeller has a plurality of peripherally spaced outlet openings.

4. A pump according to claim 3, wherein each outlet opening of the impeller is provided with a vane for imparting a rotary motion to fluid in the interior of the impeller and for guiding the fluid through the outlet opening of the impeller.

5. A pump according to claim 4, wherein each outlet opening of the impeller is provided with means for defleeting the fluid axially relative to the impeller as it passes through the outlet opening of the impeller.

6. A pump according to claim I, wherein the fluid guide means is located downstream of the impeller.

7. A multi-stage centrifugal pump comprising two or more of the pumps, according to claim 1, operatively inter-connected in series.

8. A multi-stage pump according to claim 7, wherein the impellers and the fluid guide means are mounted in a common housing and the impellers have a common drive. 

1. A centrifugal pump comprising a housing having a discharge opening, an impeller in the housing, the impeller being of a tubular form having an axial inlet opening isolated from the interior of the housing and adapted to discharge into the interior of the housing, and a guide means for guiding fluid in the interior of the housing to the discharge opening, the guide means being arranged axially with respect to the impeller and comprising a tubular member having substantially the same diameter as the impeller with an axial outlet opening and being adapted to guide fluid inwardly into the interior of the guide means, the impeller and guide means, each further comprising a hollow cylindrical member having at least one elongated opening in its peripheral surface, each said opening having two of its defining edges substantially, axially aligned, and each said opening having a vane attached to at least one of said defining edges, each said vane being jointed to a corresponding defining edge in such a manner that each said vane and said peripheral surface cooperate to form an angle therebetween.
 2. A pump according to claim 1, wherein the fluid guide means has a plurality of peripheral inlet openings, and wherein a pair of vanes is provided along the margin of each opening.
 3. A pump according to claim 1, wherein the impeller has a plurality of peripherally spaced outlet openings.
 4. A pump according to claim 3, wherein each outlet opening of the impeller is provided with a vane for imparting a rotary motion to fluid in thE interior of the impeller and for guiding the fluid through the outlet opening of the impeller.
 5. A pump according to claim 4, wherein each outlet opening of the impeller is provided with means for deflecting the fluid axially relative to the impeller as it passes through the outlet opening of the impeller.
 6. A pump according to claim 1, wherein the fluid guide means is located downstream of the impeller.
 7. A multi-stage centrifugal pump comprising two or more of the pumps, according to claim 1, operatively inter-connected in series.
 8. A multi-stage pump according to claim 7, wherein the impellers and the fluid guide means are mounted in a common housing and the impellers have a common drive. 